<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .small-font {
            font-size: 12px;
            -webkit-transform-origin-x: 0;
            -webkit-transform: scale(0.90);
        }

    </style>
</head>
<body>
    <div style="font-size: 12px">这是12px文字</div>

    <div class="small-font">这是一段文字</div>
</body>
</html>